Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Abhilash
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int arr[][] = new int[n][m];
            int sum = 0;
            int rowSums[] = new int[n];
            int colSums[] = new int[m];
            for (int i = 0; i < n; i++) {
                rowSums[i] = 0;
                for (int j = 0; j < m; j++) {
                    arr[i][j] = in.nextInt();
                    sum += arr[i][j];
                    rowSums[i] += arr[i][j];
                    colSums[j] += arr[i][j];
                }
            }
            if (sum == 0) {
                out.println(0);
                return;
            }
            int y, x;
            int miny = 100000, minx = 1000000;
            int minRows[] = new int[n];
            int minCols[] = new int[m];
            for (y = 0; n * y <= sum; y++) {
                if ((sum - n * y) % m != 0)
                    continue;
                x = (sum - n * y) / m;
                int rows[] = new int[n];
                int cols[] = new int[m];
                boolean flag = true;
                for (int i = 0; i < n; i++) {
                    if ((rowSums[i] < y) || (rowSums[i] - y) % m != 0) {
                        flag = false;
                        break;
                    } else {
                        rows[i] = (rowSums[i] - y) / m;
                    }
                }
                if (!flag)
                    continue;
                for (int i = 0; i < m; i++) {
                    if ((colSums[i] < x) || (colSums[i] - x) % n != 0) {
                        flag = false;
                        break;
                    } else {
                        cols[i] = (colSums[i] - x) / n;
                    }
                }
                if (!flag)
                    continue;
                for (int i = 0; i < n; i++) {
                    for (int j = 0; j < m; j++) {
                        if (rows[i] + cols[j] != arr[i][j]) {
                            flag = false;
                            break;
                        }
                    }
                    if (!flag)
                        break;
                }
                if (flag && x + y < minx + miny) {
                    minx = x;
                    miny = y;
                    minRows = rows;
                    minCols = cols;

                }
            }
            if (minx != 1000000) {
                out.println(minx + miny);
                for (int i = 0; i < n; i++) {
                    if (minRows[i] > 0)
                        for (int z = 0; z < minRows[i]; z++)
                            out.println("row " + (i + 1));
                }
                for (int i = 0; i < m; i++) {
                    if (minCols[i] > 0)
                        for (int z = 0; z < minCols[i]; z++)
                            out.println("col " + (i + 1));
                }
                return;
            }
            out.println(-1);
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }
}